There are various apparatus available for amplifying signals. In amplifier applications that involve the amplification and transmission of modulated signals, a premium is placed on amplifier efficiency. In communication equipment, a radio frequency power amplifier consumes a large amount of the power for the equipment. For example, in cellular telephones and in base stations, the power amplifier may dissipate more than half of the supplied power. Traditionally, efficiency of the power amplifier in such applications varies from about 5% to about 25% depending upon the peak-to-average ratio of the transmitted signals. An increase in the efficiency of the power amplifier would lead to greatly improved product results, such as improved talk time in a cellular phone.
Accordingly, there is a great need for a more efficient apparatus for amplifying signals.